UNITED STATES PATENT AND TRADEMARK OFFICE
`
`
`BEFORE THE PATENT TRIAL AND APPEAL BOARD
`
`
`POWER-PACKER NORTH AMERICA, INC.
`d/b/a GITS MANUFACTURING CO.,
`Petitioner,
`
`v.
`
`G.W. LISK CO., INC.,
`Patent Owner.
`
`
`
`Inter Partes Review of U.S. Patent 6,601,821
`
`
`DECLARATION OF
`PROFESSOR THOMAS J. LABUS
`
`
`The undersigned, Thomas J. Labus, declares under penalty of perjury
`
`pursuant to the laws of the United States of America, that the following is true:
`
`1.
`
`I received a B.S. degree in Aeronautical Engineering from Purdue
`
`University in 1968. I received a M.S. degree in Theoretical and Applied Mechanics
`
`from the University of Illinois in 1971. I have done additional graduate work in
`
`mathematics, mechanics and mechanical engineering with an emphasis on high-
`
`pressure fluid jet systems.
`
`-1-
`
`
`
`
`BEFORE THE PATENT TRIAL AND APPEAL BOARD
`
`
`POWER-PACKER NORTH AMERICA, INC.
`d/b/a GITS MANUFACTURING CO.,
`Petitioner,
`
`v.
`
`G.W. LISK CO., INC.,
`Patent Owner.
`
`
`
`Inter Partes Review of U.S. Patent 6,601,821
`
`
`DECLARATION OF
`PROFESSOR THOMAS J. LABUS
`
`
`The undersigned, Thomas J. Labus, declares under penalty of perjury
`
`pursuant to the laws of the United States of America, that the following is true:
`
`1.
`
`I received a B.S. degree in Aeronautical Engineering from Purdue
`
`University in 1968. I received a M.S. degree in Theoretical and Applied Mechanics
`
`from the University of Illinois in 1971. I have done additional graduate work in
`
`mathematics, mechanics and mechanical engineering with an emphasis on high-
`
`pressure fluid jet systems.
`
`-1-
`
`
`
`2.
`
`I have significant professional experience in mechanical engineering,
`
`including hydraulics, pneumatics, fluid mechanics, high-pressure engineering,
`
`actuation and control systems, and mechanical design and analysis.
`
`3.
`
`From 1968-1970, I was a Project Engineer at the Sundstrand
`
`Corporation, Aviation Division, working on the design and development of aircraft
`
`appendage actuation systems, including hydraulic devices and hydraulic power
`
`units. From 1971-1977, I worked as a Senior Research Engineer at IIT Research
`
`Institute, where I was responsible for the overall development and management of
`
`the High-Pressure Technology research activity. From 1977-1981, I worked as
`
`Director of R&D and Engineering Manager at EG&G Sealol, where I was
`
`responsible for product design, research and development, and quality control
`
`activities as related to mechanical seals for fluid handling applications. From 1981-
`
`1984, I worked as Chief Engineer at Hydro-Line Mfg. Co., where I was
`
`responsible for product design, and research and development as related to a line of
`
`hydraulic/pneumatic cylinders.
`
`4.
`
`From 1984-1991, I served as Associate Professor in the engineering
`
`program at the University of Wisconsin-Parkside, where I taught and/or worked in
`
`areas including thermodynamics; heat transfer; fluid mechanics; statics; strength of
`
`materials; engineering economics; engineering graphics; machine design; and
`
`applied statistics; fluid jet technology; computer-aided design for fluid,
`
`-2-
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`
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`mechanical, and thermal systems; design of automation systems using combined
`
`electronic, pneumatic and mechanical components; and the effects of high pressure
`
`processes on fluid properties. Beginning in1991, I served as Professor of
`
`Mechanical Engineering at the Milwaukee School of Engineering (MSOE). At
`
`MSOE, I helped develop fluid power option in the mechanical engineering
`
`technology program and developed long-term industrial partnerships with major
`
`companies in the field of advanced fluid power technologies. I also taught the
`
`Masters of Engineering program at MSOE in the area of mechanical engineering
`
`and fluid power. I have been Professor Emeritus at MSOE since 2012. I am active
`
`in the in the Fluid Power Institute of Applied Technology Center at MSOE that
`
`focuses on research, development, testing and evaluation in the fluid power
`
`industry.
`
`5.
`
`Based upon my experience and education, I consider myself to be at
`
`least a person of at least ordinary skill in the field of mechanical engineering, and
`
`knowledgeable as to the perspective of such a person. A person of ordinary skill in
`
`the art would have had at least a bachelor’s degree in mechanical engineering, or
`
`equivalent, with at least five years of professional work experience in the design of
`
`hydraulic and/or pneumatic devices. Superior experience or qualifications in
`
`education or experience could compensate for a deficit in the other.
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`-3-
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`6.
`
`I submit this declaration in support of Power-Packer North America,
`
`Inc., d/b/a GITS Manufacturing Co., for inter partes review of U.S. Patent No.
`
`6,601,821 (the ’821 patent). The opinions set forth here are based on my
`
`engineering training and years of experience in the field, as well as my review of
`
`the relevant materials.
`
`7. When considering the disclosures of the documents discussed below
`
`and forming the opinions in this declaration, I have attempted to view those
`
`references and the issues from the perspective of a person of ordinary skill in the
`
`art around the time of the earliest filing date for the ’821 patent, which I
`
`understand to be November 17, 2000.
`
`8.
`
`In preparing this Declaration, I have reviewed the following
`
`documents:
`
` U.S. Patent No. 6,601,821 (the ’821 patent) – Exhibits 1001/1101
`
` U.S. Patent No. 4,201,116 (Martin) – Exhibits 1002/1102
`
` Certified English translation of German Published Examined
`
`Application No. 1268494 (Eggers) – Exhibits 1004/1104
`
` U.S. Patent No. 6,006,732 (Oleksiewicz) – Exhibits 1007/1107
`
`9.
`
`I understand that, when construing the meaning of certain terms used
`
`in the claims of the ’821 patent, those terms are to be given their broadest
`
`reasonable interpretation as understood by a person of ordinary skill in the art
`
`-4-
`
`
`
`consistent with the specification of the ’821 patent, and I have endeavored to use
`
`that standard during my analyses and in forming the opinions reflected in this
`
`document.
`
`10. The claims of the ’821 patent use the terms “first fluid” and “second
`
`fluid” with reference to fluids regulated by a flow-regulating valve and a
`
`directional valve, respectively. The ’821 patent discloses specific examples of
`
`fluids that include a gas or liquid, such as “engine exhaust gas” and “engine oil.”
`
`’821 Patent at Abstract. A person of ordinary skill in the art would have been
`
`familiar with the term “fluid” and similarly would have understood the ordinary
`
`meaning of that term to indicate a substance capable of flowing, including liquids
`
`and gases. I have applied that interpretation in my analyses of the prior art.
`
`11. Two fluids, exhaust gas and oil, occupy separate flow paths within the
`
`valve assembly disclosed in the ’821 patent. The exhaust gas flows from inlet
`
`passages 30, 32 to outlet 34 within housing 12, controlled by dual-poppet head
`
`body 36. Ex. 1001 at 3:61–7:19. The oil flows from supply 76 to tank port 78 via
`
`various fluid channels through the valve assembly, regulated by spool 82. Ex. 1001
`
`at 4:28-56; Figs. 1, 2. Based on those disclosures in the ’821 patent, a person of
`
`ordinary skill in the art would have understood that the flow paths for exhaust gas
`
`and oil in the disclosed valve assembly are separate and do not commingle, each
`
`having their own source and exit points.
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`-5-
`
`
`
`12. The specification of the ’821 patent would have made clear to a
`
`person of ordinary skill in the art that the first and second fluids do not need to be
`
`different types of fluids. While the disclosed valve regulates the flow of exhaust
`
`gas, the specification states that the valve assembly can be used for “regulating not
`
`only flows of exhaust, but other fluid flows or mechanical movements that are
`
`independent of the source of fluid pressure for operating the valve assembly.” Ex.
`
`1001 at 6:61–7:3. Elsewhere, the specification defines the technical field as a valve
`
`assembly that regulates “flow of a fluid . . . by controlling the flow of a separate
`
`working fluid responsive to an electrical control signal.” Ex. 1001 at 1:11-13.
`
`Accordingly, a person of ordinary skill in the art reading the ’821 patent would
`
`have recognized that the first fluid can be any fluid, without limitation, so long as
`
`the regulated first fluid is separate from the second fluid that operates the valve
`
`assembly. In my opinion, “first fluid” and “second fluid” therefore should be
`
`interpreted to mean two separate fluids and should not be construed to require two
`
`different types of fluid. I have applied that interpretation in my analyses of the
`
`prior art.
`
`13. Claim 1 of the ’821 patent describes the claimed device as a “two-
`
`stage” valve assembly. Claim 1 of the ’821 patent also lists at least six required
`
`structures that in my opinion define a functionally complete valve assembly
`
`because the core operating components of the claimed valve assembly are listed.
`
`-6-
`
`
`
`Those listed structures include a flow-regulating valve, a double-acting actuator, a
`
`directional valve, an electrical actuator, a first surface of the double-acting
`
`actuator, and a second surface of the double-acting actuator.
`
`14. A person of ordinary skill in the art would have been familiar with
`
`two-stage valves, and such a person would have understood the ordinary meaning
`
`in the field for a two-stage valve to be a device including two valves configured
`
`such that one valve regulates the other. For example, Martin states that in “a two-
`
`stage valve, the main control spool is actuated by a double-acting actuator which is
`
`supplied by a pilot valve” and discloses that removing the control valve and
`
`preserving the pilot would turn the two-stage valve into a single-stage, Ex. 1002 at
`
`1:18-22; 5:9-14. The ’821 patent uses the term “two-stage” in the same way,
`
`describing “two-stage” valves that include two valves: a flow-regulating valve
`
`(exhaust valve 20) and another valve (spool 82) controlling the flow regulating
`
`valve. ’821 patent at 1:40-55; 3:61-67; 4:28-35; 7:13-41; Fig. 2. Based on the
`
`ordinary meaning of the term and its use in the ’821 patent, my opinion is that a
`
`person of ordinary skill in the art would have understood a “two-stage” valve to be
`
`a valve assembly including two valves configured such that one regulates the other.
`
`I have applied that interpretation in my analyses of the prior art.
`
`15. Martin refers to certain valves, including spool 27, as being a “pilot
`
`valve.” Martin at 1:18-22, 2:39-40. “Pilot valve” is a term commonly used in the
`
`-7-
`
`
`
`field, which a person of ordinary skill in the art would have understood as
`
`describing a valve that regulates another valve in a two-stage assembly, just as that
`
`term is used in Martin to describe spool 27 as a valve regulating control valve 16.
`
`Accordingly, using the term “pilot”, as in “pilot valve” or “pilot spool” in Martin,
`
`would in no way preclude such a valve or spool from being a part of a two-stage
`
`assembly.
`
`16. Claims 1 and 20 of the ’821 patent list numerous required structures
`
`that in my opinion define functionally complete valve assemblies because the core
`
`operating components of the claimed valve assemblies are listed. Those structures
`
`listed in either or both of those claims include structures such as a flow-regulating
`
`valve, a double-acting actuator, a directional valve, an electrical actuator, a first
`
`surface of the double-acting actuator, a second surface of the double-acting
`
`actuator, and a feedback mechanism.
`
`17. A person of ordinary skill in the art would have been familiar with
`
`proportional valves and would have known that such valves are configured to
`
`move in proportion with an input, such that an input of greater or lesser magnitude
`
`results in valve movements of proportionally greater or lesser magnitude,
`
`respectively. In a proportional valve, in contrast to a discrete “on/off” valve, the
`
`input and resulting proportional valve movement can be adjusted within an
`
`operating range between on and off, whether infinitely adjustable within the
`
`-8-
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`
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`operating range or adjustable to one or more discrete intermediate positions within
`
`the operating range. That ordinary understanding is consistent with how the term
`
`is used in the ’821 patent. In the ’821 patent, the disclosed valve assemblies can
`
`regulate valve position in a manner “proportional to the control signal” or
`
`“proportional to the change in the solenoid actuating force.” Ex. 1001 at 1:53-55,
`
`6:20-23. Therefore, a person of ordinary skill in the art reading the ’821 patent
`
`would have understood a “control signal” and a “solenoid actuating force” each to
`
`be a type of input that can be used for controlling valve position. Therefore, a
`
`“proportional” valve would have been understood as a valve configured to move in
`
`proportion with an input (such as an electrical control signal or a solenoid force),
`
`such that an input of greater or lesser magnitude results in valve movements of
`
`proportionally greater or lesser magnitude, respectively. I have applied that
`
`interpretation in my analyses of the prior art.
`
`18.
`
`I have been provided color-coded versions of Figures 2 and 3 of the
`
`’821 patent, reproduced below.
`
`-9-
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`-10-
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`-10-
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`
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`Based on my review of the ’821 patent, the color-coding added to those images
`
`accurately identifies components in the illustrated device, including solenoid 116
`
`(purple), spool 82 (orange) of four-way valve 22, flow pathways for oil as the
`
`“second” fluid (green), piston head 62 within double-acting cylinder 24 (red),
`
`poppet head body 36 (blue) of exhaust valve 20, flow pathways for exhaust gas as
`
`the “first” fluid (yellow), and feedback spring 26 (gray). ’821 patent at 3:61-67,
`
`4:20-64, 5:21-42.
`
`19.
`
`I have been provided color-coded versions of Figures 1 and 2 of
`
`Martin, reproduced below.
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`-11-
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`
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`Based on my review of Martin, the color-coding added to those images accurately
`
`identifies components in the illustrated device, including solenoid 12 (purple),
`
`spool 27 (orange), flow pathways for a fluid (green) supplied by pump 28, piston
`
`45 of double-acting cylinder 46 (red), spool 20 (blue) of main control valve 16,
`
`flow pathways for another fluid (yellow), and feedback spring 75 (gray). Martin at
`
`1:37-43, 2:14-61, 3:41-65.
`
`20.
`
`I have been provided a color-coded version of Figure 1 of Eggers,
`
`reproduced below.
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`-12-
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`
`
`Based on my review of Eggers, the color-coding added to that image accurately
`
`identifies components in the illustrated device, including an electric stepper motor
`
`15 (purple), a second valve (orange) including control slide 16, flow pathways for
`
`compressed air (green), a pneumatic piston drive 6 (red) including working rod 3
`
`and piston 5,slide 2 (blue) of valve 1, flow pathways for a fluid (yellow), , and a
`
`feedback arm 4 (gray). Eggers at 4:18-25, 5:1-25.
`
`21.
`
`I have been provided a color-coded version of Figure 2 of
`
`Oleksiewicz, reproduced below.
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`-13-
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`
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`Based on my review of Oleksiewicz, the color-coding added to that image
`
`accurately identifies components in the illustrated device, including linear actuator
`
`52 (purple), flow pathways for exhaust gas (yellow) through valve 50, and valve
`
`stem 54 with valve bodies 60 and 70 (blue). Oleksiewicz at 2:48–3:16, 3:60–4:3.
`
`22.
`
`In my opinion, Martin discloses a two-stage valve assembly. Martin’s
`
`disclosed valves “can be either single or two-stage,” Martin at 1:59-62, and the
`
`embodiments illustrated in the drawings are two-stage valves with spool valve 27
`
`and main control valve 20, Martin at 5:9-14, Fig. 1. In the disclosed valve
`
`assemblies, spool valve 27 regulates control valve 20. Martin at 3:57–4:2.
`
`Accordingly, a person of ordinary skill in the art would have understood that
`
`Martin discloses a two-stage valve assembly.
`
`23. Martin’s disclosed device is also a proportional control valve
`
`assembly. The disclosed valve is configured such that “a small movement of the
`
`-14-
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`
`
`solenoid core will cause a proportionally larger movement of the main control
`
`valve spool.” Martin at Abstract, also at 4:5-10. Furthermore, Martin discloses that
`
`the disclosed control valve spool 20 moves increasing distances as a greater
`
`electrical signal is applied to the solenoid core. Martin at 4:21-44. Accordingly,
`
`Martin discloses a proportional control valve assembly that can assume a range of
`
`positions in proportion to an input. I also note that Martin repeatedly describes its
`
`valve assemblies as “proportional,” including in the title of the patent, using that
`
`term in a manner consistent with its ordinary use in the field and in the ’821 patent.
`
`Martin at 5:18-20.
`
`24. Martin discloses that movements of control valve spool 20 of control
`
`valve 16 open and close a fluid flow path for a first fluid between motor port cavity
`
`25 and drain 26. Martin at 2:32-35; 3:60-62, Fig. 1. A separate, second fluid is
`
`supplied from pump 28 and flows in a closed circuit regulated by spool 27 to drive
`
`movement of spool 20. Martin at 2:39-61; 3:57-65, Fig. 1. The first and second
`
`fluids in Martin remain separate within the valve assembly and have separate
`
`source and drain passages. Martin at 2:25-53, Fig. 1. A person of ordinary skill in
`
`the art would have known that spool 20 is a flow-regulating valve, and that
`
`moving spool 20 to regulate flow as disclosed by Martin controls the flow rate of a
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`first fluid (between cavity 25 and drain 26) using fluid pressure from a separate
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`second fluid supplied from pump 28.
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`-15-
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`25. A person of ordinary skill in the art would have been familiar with
`
`directional valves, which are valves that direct a fluid among different flow
`
`pathways. A person of ordinary skill in the art would have understood that
`
`Martin’s spool 27—like spool 82 disclosed in the ’821 patent—is a directional
`
`valve that directs a fluid among different flow pathways. Martin at Figs. 1, 2.
`
`26.
`
`In Martin, a controller device provides the electrical signal to the
`
`solenoid unit 12. Martin at 4:18-20. Upon energizing one of the solenoid coils 54
`
`or 55, “the force balance on pilot spool 27 changes causing a slight movement due
`
`to the added force from the solenoid,” causing movement of spool 27 and thus
`
`regulating fluid flows to double-acting cylinder 46 and moving piston 45. Martin at
`
`3:45-62. Martin’s disclosed solenoid unit 12 converts an electrical signal from a
`
`controller device into a force on a directional valve (spool 27), regulating a second
`
`fluid flow to double-acting cylinder 46 to adjust the position of piston 45 within
`
`double-acting cylinder 46. Martin at 2:61-63, 3:45–4:2. Energizing coil 54 moves
`
`spool 27 to the left, causing land 31 to slightly open motor port 33 to pressure from
`
`pump 28 and land 32 to open motor port 34 to drain, thereby causing piston 45 and
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`control valve spool 20 to move to the right opening main motor port cavity 25 to
`
`drain 26. Martin at 3:49-62. A person of ordinary skill in the art would have known
`
`that energizing coil 55 would move spool 27 to the right and have the opposite
`
`effect, causing land 32 to open port 34 to pump 28 to apply pressure of the second
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`-16-
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`
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`fluid to chamber 48 through passage 29, motor port 34, and passage 50, and open
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`port 33 and chamber 47 via passage 49 to drain, causing piston 45 and control
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`valve spool 20 to move left, closing motor port cavity 25 to drain 26. Martin, Figs.
`
`1, 2.
`
`27. Martin’s valve includes a double-acting cylinder 46 defined by
`
`enlarged bore 44 and piston 45 slidably positioned within bore 44, attached to
`
`spool 20, and powered by the second fluid from pump 28. Martin at 2:55-58, Fig.
`
`1. Double-acting cylinder 46 defines two chambers 47 and 48—chamber 47 is
`
`connected with motor port 33 via passage 49, and chamber 48 is connected to
`
`motor port 34 via passage 50. Martin at 2:58-61. I note that Martin’s Figure 1
`
`erroneously labels the passage connected to motor port 34 twice (as 50 and 49), but
`
`Figure 2 correctly labels the passage connected to motor port 33 as passage 49. A
`
`person of ordinary skill in the art would have recognized Martin’s double-acting
`
`cylinder 46 as a double-acting actuator because the second fluid powers movement
`
`of spool 20 and attached piston 45 by exerting force on piston 45. The double-
`
`acting cylinder 46 functions as a hydraulic actuator powered by the second fluid
`
`and including a piston dividing bore 44 into two chambers in the disclosed two-
`
`stage valve. Martin at 1:18-22. Because piston 45 can move in two directions (right
`
`or left), a person of ordinary skill in the art would have recognized piston 45 as a
`
`double-acting piston.
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`-17-
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`28.
`
`In the Martin valve assembly, piston 45 has a first surface exposed to
`
`chamber 47 and a second surface exposed to chamber 48. I have been provided
`
`annotated versions of Martin’s Figure 1, reproduced below.
`
`
`
`The annotated figure on the left shows the first surface of piston 45 marked with
`
`red, and the annotated figure on the right shows the second surface of piston 45
`
`marked with red. Fluid pressure from pump 28 can be applied through motor port
`
`33 to chamber 47 or through motor port 34 to chamber 48, depending on the
`
`position of valve 27. Martin at 3:57-65; 4:21-36. Fluid pressure applied (i) to
`
`chamber 47 acts on piston 45 at the first surface, causing piston 45 and attached
`
`spool 20 to move right, thus opening valve spool 20, and (ii) to chamber 48 acts on
`
`piston 45 at the second surface, causing piston 45 and attached spool 20 to move
`
`left, thus closing valve spool 20. Martin at 3:57–4:36, Fig. 1.
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`-18-
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`
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`29. Valve 27 also regulates flows of fluid from chambers 48 and 47 within
`
`double-acting cylinder 46, and thus from the first and second faces of piston 45, by
`
`regulating flows between motor port 34 or motor port 33 and drain passage 38.
`
`Martin, Figs. 1-2. For example, moving spool 27 to the left not only opens motor
`
`port 33 (and thus chamber 47 via passage 49) to pressure from pump 28, but also
`
`opens motor port 34 (and thus chamber 48 via passage 50) to drain. Martin at 3:57-
`
`60. Conversely, moving spool 27 to the right would open motor port 33, passage
`
`49, and chamber 47 to drain. Martin Figs. 1-2. In other words, moving spool 27 left
`
`to a first operating position “connect[s] the pressure source with a first chamber of
`
`the double acting cylinder while connecting the opposing second chamber of said
`
`cylinder to drain,” and moving spool 27 right to a second operating position
`
`“connect[s] the pressure source with the second chamber while draining the first
`
`chamber.” Martin at 5:30-36. A person of ordinary skill in the art would have
`
`recognized that by selectively opening chambers 47 and 48 to drain passage 38,
`
`spool valve 27 regulates flows of fluid from the first and second faces,
`
`respectively, of piston 45 to a drain (also known as a tank port) within double-
`
`acting cylinder 46.
`
`30. A person of ordinary skill in the art would have known that a four-
`
`way valve is a valve that regulates fluid flow among four different flow pathways.
`
`Martin’s spool valve 27 is a four-way valve because it regulates fluid flow among
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`-19-
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`
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`four different pathways: passage 33, passage 34, drain cavity 38, and passage 29.
`
`Martin at Abstract, 2:39-53, 5:27-30, 6:47-50, Figs. 1-2.
`
`31. Martin discloses feedback spring 75. Martin at 3:28, Fig. 1. At one
`
`end, feedback spring 75 bears against the left end of spool 27, and, at the other end,
`
`spring 75 connects with double-acting cylinder 46, aligning with piston 45 attached
`
`to spool 20 within double-acting cylinder 46. Martin at 3:20-22, Figs. 1-2.
`
`Feedback spring 75 provides feedback between double-acting cylinder 46 and
`
`spool 27. Upon moving Martin’s spool 27 left to the first directional valve position,
`
`spool 20 moves to the right and spring 75 is compressed, increasing the feedback
`
`force on pilot spool 27. When the increases match the added force created by the
`
`solenoid 12, pilot spool 27 will return to neutral. Martin at 3:65-68. In the neutral
`
`position, spool 27 blocks cylinder port passages 33 and 34, thus blocking
`
`differential flows to chamber 47 (including the first surface of piston 45), chamber
`
`48 (including the second surface of piston 45), pump 28, and drain 38. Martin at
`
`2:42-44, Figs. 1, 2. Upon moving spool 27 to the right, fluid pressure in chamber
`
`48 moves spool 20 to the left, decompressing spring 75 and urging spool 27 back
`
`toward neutral. Martin, Fig. 1.
`
`32.
`
`In Martin, piston 45 of double-acting cylinder 46 is attached to spool
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`20. Martin at 2:56-57. The position of spool 20 (and attached piston 45) is
`
`determined by the electrical signal supplied to solenoid 12. Martin at 3:49–4:2,
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`-20-
`
`
`
`4:21-23. When spool 20 and piston 45 move rightward in the opening direction,
`
`they can move through a continuum of positions depending on the amount of force
`
`applied by the feedback spring on spool 27, set against the force applied by the
`
`solenoid, until the forces match and spool 27 returns to neutral “and control valve
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`spool 20 will stop at a precise position.” Martin at 3:62–4:2. Thus, the position of
`
`piston 45 within double-acting cylinder 46 varies through a range of positions
`
`corresponding to the magnitude of compression on feedback spring 75.
`
`33. Martin discloses that the “movement of the control valve spool 20 is
`
`proportional to the rate of spring 75, assuming a constant solenoid force. The
`
`movement of the control valve spool is also proportional to the force generated in
`
`the solenoid, assuming the spring rate of spring 75 remains constant.” Martin at
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`4:3-10. “The greater the electrical signal applied to the solenoid coil, the farther the
`
`control valve spool 20 moves before it reaches its equilibrium point.” Martin at
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`4:21-23. As spool 20 moves, force is applied to spring 75, and when “force on the
`
`spring 75 matches the force created by the solenoid 12, pilot spool 27 will return to
`
`neutral and valve spool 20 will stop at a precise location determined by the
`
`electrical signal supplied by the solenoid 12.” Ex. 1002 at 3:66–4:2. Because
`
`solenoid 12 apply varying levels of force to move spool 27 varying distances left
`
`or right and thus compress or decompress spring 75, a person of ordinary skill in
`
`-21-
`
`
`
`the art would have recognized that changes in compressive force of spring 75 relate
`
`to changes in the force from solenoid 12.
`
`34.
`
`In Martin’s main control valve 16, “spool bore 21 is axially aligned
`
`with an enlarged bore 44 which contains a piston 45 slidably positioned therein and
`
`attached to spool 20. Piston 45 and bore 44 define a double acting cylinder 46
`
`including two chambers 47 and 48.” Martin at 2:54-58. Piston 45 and control valve
`
`spool 20 are attached to one another and move freely together in response to
`
`pressures of the second fluid applied to the chambers of the double-acting cylinder.
`
`Martin at 3:58-62, Fig. 1.
`
`35. Martin discloses that main control “valve 16 is a closed-center type
`
`control valve.” Martin at 2:35-36. A person of ordinary skill in the art reading
`
`Martin would have known that Martin’s closed-center control valve 16 is pressure
`
`balanced with respect to the regulated first fluid because closed-center type spool
`
`valves are necessarily pressure balanced. In the case of Martin’s valve 16, a person
`
`of ordinary skill in the art would have known that the pressure, tank, and both work
`
`ports on the closed-center valve 16 are all isolated from the pressure port when the
`
`valve is closed so that pressure does not influence the movement or position of the
`
`valve spool.
`
`36. Spring 75 is positioned between spool 20 and spool 27. Martin at Fig.
`
`1. “As spool 20 moves to the right, spring 75 is compressed, increasing the force
`
`-22-
`
`
`
`on pilot spool 27.” Martin at 3:65-68. A person of ordinary skill in the art would
`
`have known that the feedback force from spring 75 on spool 27 would relate to the
`
`spacing between spool 20 (and attached piston 45) and spool 27. Feedback force
`
`would increase as spool 20 moves closer to spool 27, until the feedback force from
`
`spring 75 matches the force from solenoid 12, at which time spool 27 would move
`
`to the right, increasing the spacing between spools 20 and 27. Martin at 3:65–4:2
`
`37. Spool 27 and solenoid core 56 are balanced between the two springs
`
`65 and 75 in their neutral positions when the control valve spool 20 is neutrally
`
`positioned. Martin at 3:25-37. Spring 65 imparts a biasing force on spool 27
`
`opposing spring 75, just as spring 130 disclosed in the ’821 patent imparts a
`
`biasing force on spool 82 opposing spring 26. Martin at 3:42-57, Fig. 1; ’821
`
`patent at 5:6-10, Fig. 2. A person of ordinary skill in the art would have recognized
`
`that movement of the spool 20 to the left (i) increases the spacing between the
`
`combined spool 20 and piston 45 and the directional valve spool 27, (ii) the bias
`
`spring 65 exerts a force on the directional valve spool 27 causing it to move to the
`
`left (iii), movement of directional valve spool 27 to the left increases fluid pressure
`
`in chamber 47 of the double acting cylinder 46 and moves combined spool 20 and
`
`piston 45 to the right, decreasing the spacing between these components and
`
`directional valve spool 27 and causing the spool 27 to return to its neutral position.
`
`-23-
`
`
`
`The foregoing description of the bias mechanism in Martin is identical to how the
`
`bias mechanism functions in the ’821 patent.
`
`38. Poppet-head valves were well known to persons of ordinary skill in
`
`the art before the time of the ’821 patent, as were pressure-balanced valves. For
`
`example, Oleksiewicz discloses that “balanced valve arrangements are per se
`
`known.” Oleksiewicz at 1:17.
`
`39.
`
`In Oleksiewicz, valve 50 includes two valve bodies 60 and 70
`
`attached to stem 54, which engage with corresponding inlet ports 62 and 72,
`
`respectively. Oleksiewicz at 2:62–3:16. The other end of stem 54 engages with
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`linear actuator 52, such as a solenoid, allowing linear actuation of the valve.
`
`Oleksiewicz at 1:62-63; 2:52-64. A person of ordinary skill in the art would have
`
`recognized valve bodies 60 and 70 as poppet heads because during operation they
`
`seat directly on another surface, in this case inlet ports 62 and 72.
`
`40. Ports 62 and 72 and valve bodies 60 and 70 of Oleksiewicz may be of
`
`identical size, and Oleksiewicz discloses that exhaust pressure applied against the
`
`tip 66 of first valve body 60 will be compensated for by the exhaust pressure
`
`applied against the inner surface 82 of the second valve body 70, “the valve 50
`
`thus remaining balanced between the opposing forces acting thereupon.”
`
`Oleksiewicz at 3:9-16; 3:60-66. Therefore, a person of ordinary skill in the art
`
`would have known that Oleksiewicz discloses a dual poppet-head valve that is
`
`-24-
`
`
`
`pressure-balanced with respect to the exhaust fluid flows from inlet passages 18
`
`and 20.
`
`41. A person of ordinary skill in the art would have known that spool
`
`valves are often relatively leaky, while poppet-head valves are known to be
`
`substantially more efficient in terms of minimizing leakage. Accordingly, a person
`
`of ordinary skill in the art reading Martin would have been motivated to substitute
`
`a poppet-head valve, such as the one disclosed by Oleksiewicz, for the spool-based
`
`flow-regulating valve disclosed in Martin to reduce leakage and improve
`
`efficiency. Because Martin and Oleksiewicz both disclose prior art flow-regulating
`
`valves, and because both Martin’s spool 20 and Oleksiewicz’s valve are configured
`
`for linear actuation, a person of ordinary skill in the art naturally would have
`
`looked to Oleksiewicz for a poppet valve to replace spool 20 in Martin’s main
`
`control valve 16.
`
`42.
`
`Incorporating Oleksiewicz’s pressure-balanced poppet head valve into
`
`the Martin design in place of spool 20 would have been well within the abilities of
`
`a person of ordinary skill in the art. Furthermore, a person of ordinary skill in the
`
`art would have reasonably expected to succeed in doing so because the
`
`combination of Martin and Oleksiewicz would have represented a predictable use
`
`of well-known prior art components according to their established functions.
`
`-25-
`
`
`
`43. A person of ordinary skill in the art would have been familiar with
`
`pressure-balanced valves and would have known that valves pressure-balanced
`
`with respect to the regulated fluid are desirable because they can be moved using
`
`relatively small forces. Accordingly, a person of ordinary skill in the art would
`
`have been motivated to incorporate a pressure-balanced valve into the Martin
`
`design as control valve 16 to improve efficiency and would have had a reasonable
`
`expectation of success in doing so based on the straightforward and predictable use
`
`of simple, well-k
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